Mounting structure for spherical shaped underwater transducer

ABSTRACT

A spherical underwater transducer is flexibly suspended by means of a rubber-like belt equatorially surrounding the sphere. The belt has mounting brackets molded therein and undercut cooling slots formed therein.

United States Patent 1 [111 3,716,827 Massa [4 1 Feb. 13, 1973 [s 1MOUNTING STRUCTURE FOR [561 Reierems Cited SPHERICAL SHAPED UNDERWATERUNITED STATES PATENTS 2,610,018 9/l952 Rettinger "340/8 R [75] Inventor:Frank Massa, Cohasset, Mass. S ke1 310/9 1 ason ['73] Assignee: MassaDivision Dynamics Corporation of America, Hingham, Mass. Z"' t g dBorchelt $818 an xammer- U Or [22] Filed: Aug. 3, 1970 Attorney-LouisBernat 211 Appl.No.: 60,258 [57] ABSTRACT 521 US. Cl. ..340/s s,310/9.1,340m A SPherical underwater transiducer is flexibly H Int Cl G0" n00suspendgd by means of a rubber-like belt equatorlally I Surroun g theSphere The be t has mounting [58] Fleld of Search ..3lO/9.1, 9.7;

brackets molded therein and undercut cooling slots formed therein.

9 Claims, 4 Drawing Figures HIllllllIll llillllllll IIlllIlllL MOUNTINGSTRUCTURE FOR SPHERICAL SHAPED UNDERWATER TRANSDUCER This inventionrelates to a flexible mounting structure, and more particularly to meansfor holding a spherically shaped transducer in a desired position in anarray frame.

This invention is particularly well adaptable for mounting andsupporting an inertial electromagnetic, spherical, underwater transducersuch as that described in U.S. Pat. No. 3,319,220 issued on May 9, 1967,to Frank Massa, Jr., and assigned to the assignee of this application.The invention enables the transducers of this type to freely'executetranslational vibrations into the surrounding medium within which anarray is immersed. More particularly, a spherically shaped transducer isflexibly suspended by a belt-like band of pliable, rubber-like materialwhich is fitted around the periphery of the transducer. This band iscontoured on its inner and outer surfaces in a manner such that thesphere is held captive and, at the same time, is free to vibraterelative to the fixed frame structure to which the transducer isattached.

Accordingly, an object of this invention is to provide an efficientmounting for a spherical transducer. More particularly, an object is toenable the transducer to freely execute oscillatory vibrations along anaxis of the sphere. Here, an object is to prevent restrictivevibrational interference from the mounting structure.

Another object of this invention is to provide a flexible mountingstructure with an inner surface contoured to conform to the externalsurface of the transducer. In this connection, an object is to conformthe transducer and the flexible support in the region where the mountingis to be attached. Further, an object is to make the outer contour ofthe belt conform to and tightly fit in an opening in a mountingstructure within which the trans ducer is to be operationally attached.

A still further object of this invention is to provide a flexible mountfor a spherical underwater transducer with the mount being attached tothe surface of the transducer in the vicinity of its equatorial region.Here, an object is to provide such a mount with its inner surfaceundercut in regions to provide improved cooling, for the transducer,during high power underwater operation.

In keeping with an aspect of the invention, these and other objects areprovided by a flexible belt-like mounting structure which may bestretched over and cemented to the outer surface of the equatorialregion of a spherical transducer. The belt has a plurality of rigidmounting brackets which are bonded securely about the periphery of theflexible belt-like mounting structure. These mounts permit an exactplacement and assembly of the flexibly-mounted transducer element in arigid frame structure or array frame.

This invention contemplates other objects, features and advantages whichwill become more fully apparent from the following detailed descriptionwhen taken in conjunction with the accompanying drawings whichillustrate a preferred embodiment and in which:

FIG. 1 is a front plan view of a spherical transducer incorporating oneillustrative embodiment of the flexible mounting structure;

FIG. 2 is a cross-sectional view of the mounting structure taken alongthe line 2-2 of FIG. l-with the spherical transducer being shown in afull non-sectional view within the cross-sectioned peripheral mountingstructure;

FIG. '3 shows essentially the same cross-sectional view of the mounting(as seen in FIG. 2) except that the spherical transducer is removed sothat more details of the flexible belt-like mounting structure may beseen; and

FIG. 4 is a rear plan view of the assembled structure illustrated inFIG. 1.

The same reference characters identify the same parts throughout thevarious figures. More particularly, the reference character 10identifies a spherical underwater transducer, which, for example, may beof the type described in U.S. Pat. No. 3,319,220. This particulartransducer design is well adapted for low frequency, high power, deepwater usage. In general, this patent shows a spherically shapedenclosure, driven as a single whole unit in a translatory mode ofvibration responsive to electromagnetic forces generated between thespherical outer housing and internal spring-mounted I inertial massmembers.

In order to mount the spherical transducer element in a supporting rigidframe, and at the same time permit unimpeded oscillatory vibration ofthe spherical element, a flexible belt-like band 12 is equatoriallyattached to the periphery of the sphere. The plane of this equatorialattachment lies at right angles to the axis of transducer vibrations.The attachment may be accom plished by cement or other suitable means.

This band may, for example, be molded rubber. Metal brackets 13 arefirmly secured to the periphery of the rubber belt 12. For example,these brackets may be inserted into a mold during the manufacture of thebelt member 12. Each bracket 13 is provided with a hole 14 through whicha bolt may be passed for securely attaching the assembly to a rigidstructure.

The band or belt 12 reliably secures the transducer in place and yetenables it to remain free to vibrate in any direction. For example, thetransducer might be attached to a rigid structure, such as the rearsurface of the underwater horn illustrated in FIG. 1 of U.S. Pat. No.3,319,220. There, the spherical transducer radiates acoustic energythrough a horn opening. According to another example, the rigidstructure might also be an array frame which is designed to locate anumber of transducers in a desired configuration for producing aspecified radiation beam pattern and sound power level. Such an arraystructure is illustrated in a copending application Ser. No. 61,198,filed Aug. 5, 1970, entitled BAFFLE STRUCTURE FOR UN- DERWATERTRANSDUCER ARRAY," and assigned to the assignee of this invention.

The spherical transducers of this invention may be applied to large,high power underwater sound source devices weighing as much as athousand pounds each. These devices develop several kilowatts ofacoustic power. Thus, it is necessary for the transducers to be securelyheld in a desired location. At the same time, the transducers should befree to vibrate without restriction in order to operate efficiently.

This basic objective of secure support and vibrational freedom isachieved by shaping the inner surface of the belt-like member 12 to fitthe spherical shape of the transducer to which it is attached. The outersurface of the member 12 is shaped in the form of a cylinder. When theouter surface of the flexible mount 12 is confined within a rigidcylindrical opening, it provides a mounting structure for thetransducer. The spherical transducer remains securely cradled into itsexact nested position when ,the brackets l3 are bolted to matingmounting brackets (not shown) located about the periphery of the rigidcylindrical opening in the mounting structure.

it is necessary or desirable to provide additional cooling forpreventing an overheating of the transducer when it operates at highpower levels. Therefore, undercut regions or slots 15 and 16 arerecessed into the inner surface of the flexible band 12. These slots 15provide a communicating passageway between the equatorial region of thesphere l and one edge of the band 12. The slots 16 provide similarcommunicating passageways between the equatorial region of the sphereand the other edge of the band 12. These undercut slots serve twodesirable functions. First, they allow water to enter and make contactwith the equatorial region of the transducer housing shell, therebyconducting heat away from the transducer housing. The resulting degreeof cooling is far greater than it would be if the rubber belt 12 weresolid. If, for any reason, a solid belt must be used, it would be wellto provide an increased thermal conductivity covering over theequatorial area of the sphere.

The presence of the slots and 16 also provides increased compliance inthe wall thickness of the rubber belt 12. Thus, the belt may be easilyforced into a tight cylindrical opening to maintain a desirableinterference fit therein. The interference fit of the compliant rubberbelt structure, in the cylindrical structural openings, has an advantagesince it damps any mechanical vibrations of the frame. This is desirablesince it prevents vibration damage to the structure that might otherwiseoccur under non-damped, high-amplitude operation.

The mounting structure described thus far is primarily developed forefficiently mounting a spherically shaped transducer. However, it couldalso be used advantageously with a cylindrical shaped transducer, suchas, for example, the cylindrical transducer 10 illustrated in U.S. Pat.No. 3,205,476, issued on Sept. 7, 1965. For the cylindrical transducer,both the inside and outside'surfaces of the flexible belt structure 12should have a conforming cylindrical shape.

While I have shown and described a specific embodiment of the presentinvention, it should be understood that various modifications andalternative constructions may be made without departing from the truespirit and scope of the invention. Therefore, it is intended by theappended claims to cover all equivalent and alternative constructionswhich might fall within their true spirit and scope.

a substantially spherical shape for executing translatory vibrationsalong a particular axis when energized by said signals, means forflexibly and se'curely'mounting said transducer in a rigid structure,said mounting means including a belt of resilient material equatoriallysurrounding the external surface of said transducer which lies, in aplane at right angles to said axis of vibration, and fastening meansassociated with said belt of resilient material for securely retainingsaid transducer in an accurate position relative to said rigidstructure.

2. The system of claim 1 wherein said belt includes undercut regions incontact with said sphere,'said undercut regions enabling water to reachthe equatorial region of said sphere when it is operating under water.

3. The system of claim 2 wherein said undercut regions alternately enterfrom opposite sides of said belt and extend toward the middle of saidbelt.

4. A transducer mounting for a spherical vibratile system, said systemcomprising an electroacoustic transducer means having a substantiallyspherical shape for executing translatory vibrations along a particularaxis, said mounting structure including a belt of resilient materialsurrounding the external surface of the equatorial region of saidtransducer, said equatorial region containing a circle of maximumdiameter on the surface of said transducer which lies in a plane atright angles to said axis of vibration, said belt of resilient materialbeing characterized in that regions of the material are undercut atspaced intervals around the inner peripheral surface of said belt whichis in contact with the surface of said transducer.

5. The invention in claim 4 being further characterized in that theinner surface of said resilient belt is contoured to have a concaveshape which mates with and compliments the external convex surface ofsaid spherically shaped transducer.

6. The invention in claim 5 being still further characterized in thatthe outer surface of said resilient belt is contoured to have acylindrical shape, with the axis of said cylinder lying along theparticular axis of translatory vibrations.

7. The invention in claim 4 and a bonding agent between the innersurface of said resilient belt and the outer mating surface of saidtransducer.

8. The invention in claim 4 being still further characterized in thatsaid resilient belt is a molded elastomer material.

9. The invention in claim 8 and metal mounting brackets molded into saidresilient belt for securing the transducer and belt assembly to a rigidframe.

1. A vibratile system for the generation of acoustic energy responsiveto electrical signals, said system comprising an electroacoustictransducer means having a substantially spherical shape for executingtranslatory vibrations along a particular axis when energized by saidsignals, means for flexibly and securely mounting said transducer in arigid structure, said mounting means including a belt of resilientmaterial equatorially surrounding the external surface of saidtransducer which lies in a plane at right angles to said axis ofvibration, and fastening means associated with said belt of resilientmaterial for securely retaining said transducer in an accurate positionrelative to said rigid structure.
 1. A vibratile system for thegeneration of acoustic energy responsive to electrical signals, saidsystem comprising an electroacoustic transducer means having asubstantially spherical shape for executing translatory vibrations alonga particular axis when energized by said signals, means for flexibly andsecurely mounting said transducer in a rigid structure, said mountingmeans including a belt of resilient material equatorially surroundingthe external surface of said transducer which lies in a plane at rightangles to said axis of vibration, and fastening means associated withsaid belt of resilient material for securely retaining said transducerin an accurate position relative to said rigid structure.
 2. The systemof claim 1 wherein said belt includes undercut regions in contact withsaid sphere, said undercut regions enabling water to reach theequatorial region of said sphere when it is operating under water. 3.The system of claim 2 wherein said undercut regions alternately enterfrom opposite sides of said belt and extend toward the middle of saidbelt.
 4. A transducer mounting for a spherical vibratile system, saidsystem comprising an electroacoustic transducer means having asubstantially spherical shape for executing translatory vibrations alonga particular axis, said mounting structure including a belt of resilientmaterial surrounding the external surface of the equatorial region ofsaid transducer, said equatorial region containing a circle of maximumdiameter on the surface of said transducer which lies in a plane atright angles to said axis of vibration, said belt of resilient materialbeing characterized in that regions of the material are undercut atspaced intervals around the inner peripheral surfacE of said belt whichis in contact with the surface of said transducer.
 5. The invention inclaim 4 being further characterized in that the inner surface of saidresilient belt is contoured to have a concave shape which mates with andcompliments the external convex surface of said spherically shapedtransducer.
 6. The invention in claim 5 being still furthercharacterized in that the outer surface of said resilient belt iscontoured to have a cylindrical shape, with the axis of said cylinderlying along the particular axis of translatory vibrations.
 7. Theinvention in claim 4 and a bonding agent between the inner surface ofsaid resilient belt and the outer mating surface of said transducer. 8.The invention in claim 4 being still further characterized in that saidresilient belt is a molded elastomer material.